In Tag Panel, the artist dropdown select box is always empty

I have enabled the library function, but when entering some artist names the drop down select box is always empty. What do I do wrong??

I expected, that all artist names (I use the “familyname, prename” form) once entered for one song, are available subsequently when editing next songs.

Additional question: when I have to enter multiple artist names for a song, I hope to be able to select a first name, then enter manually a “;” and then select the next name. Is that possible?

After not using mp3tag for a long time, maybe my problems are due to me being a “newbe” again - sorry!

Thanks for any advise!

The library function is only for internal housekeeping purposes.
If you want to see pre-defined values in a tag panel field, you have to add them manually.
See the documentation for more details how to add custom values:

No.
In any case, the ";" is no specified separator for several values in a single field.